“Spring water” describes the source, not the composition, and compositions vary enormously.
What spring water is
Water from an underground source, bottled at source, with its natural mineral content.
That content depends entirely on the geology it passed through — which can mean 30 ppm or 400 ppm of dissolved solids.
The good ones
Low bicarbonate, moderate hardness. Read the label:
Bicarbonate under 50 mg/L, ideally under 30. Calcium 20 to 50 mg/L. Low sodium.
Several widely available spring waters fit this and brew beautifully.
The bad ones
Waters drawn through limestone can carry 300 to 400 mg/L bicarbonate. Excellent to drink, and they make flat, dull coffee and scale a machine quickly.
Some premium mineral waters are the worst offenders — high mineral content is their selling point.
Filtered tap water
Consistent, cheap and available. A carbon jug filter removes chlorine and reduces hardness.
Its ceiling is set by what comes out of your tap. In a very hard area, a jug filter will not get you into range on its own.
How to decide
Test your filtered tap water. If hardness and alkalinity are in range, use it — it is cheaper and produces no plastic.
If not, find a bottled water with good numbers and compare side by side.
The cost reality
Bottled water for daily brewing adds up quickly. Use it to learn what you like, then reproduce it.
Last reviewed 8 August 2026